Digital vector generator which causes the electron beam to move in the largest possible increment by sensing if the line is divisible by 2{11 .

ABSTRACT

A circuit for use in a cathode ray tube vector display device for controlling the speed at which the electron beam is made to transverse the screen. The circuit senses whether the length of the line segment yet to be formed is evenly divisible by 2,4,8. . . 2n and causes the electron beam to move in the largest possible increment.

United States Patent 1191 Granberg et al. Apr. 17, 1973 DIGITAL VECTOR GENERATOR [56] References Cited WHICH CAUSES THE ELECTRON NI BEAM TO MOVE IN THE LARGEST U TED STATES PATENTS POSSIBLE INCREMENT BY SENSING 3,320,409 5/1967 Larrowe .235/151 IF THE LINE [5 DIVISIBLE BY 3,403,286 9/1968 Carlock et al. ..314/18 7 3,422,304 l/l969 Thorpe ..3l5/l8 1 lnvemorsl Mam"! cranbel'g, Mmneapolls; 3,459,926 8/1969 Heilweil et al.... ..340/324 1 x Hubert Mueller, Jr-. g. 3,509,542 4/1970 Ehrman ..340/324.1x both of Minn.

[73] Assignee: Sperry Rand Corporation, New Primary Emminer cafl Q f York Assistant 'ExaminerJ. M. Potenza Att0rneyThomas J. Nikolai, Charles A. Johnson and [22] Filed: July 17, 1969 John p Dority 211 Appl. No.5 871,161

1 [57] ABSTRACT Rld.."l'tiDta' 1 e ate U S App on a A circuit for use in a cathode ray tube vector display Di ision of Ser. No. 569,48l, Aug. 1, 1966, Pat. No. device for controlling the speed at which the electron 3,510,634- 4 I beam is made to transverse the screen. The circuit senses whether the length of the line segment yet to be [52] US. Cl. ..3l5/l8, 340/324 A formed is evenly divisible by 2 4 2n and causes [51] Int. Cl ;.H0l 29/70 the electron beam to move in the largest possible 58 Field 61 Search ..3l5/l8; 340/3241, crement 2 Claims, 40 Drawing Figures BUFFER (P96 s-ee 5-7a PATENTEDAPRIYIQB. 3.728575 SHEET 010F23 8 fh OCTAL [0| 7 x POSITION Y POSITION |||2--4I5 l4|l5 24 q oo \OQOQQQ v VECTOR WORD I'l l 'TANGENT OR COTANGENT I 'x OR Y FINAL II '2 3'4 4l 5 PATENfED R I 71m 'Lx men) [X STOP s x 5-60 5-22 gig-54s Lcommne l5) CONTROL POSITION WORD "i/ I r5'4o LINE 5'2 cone (546 OCTANT 15 5 28 5 38 s DECODER WORD VECTOR worm FLAG l 25 (FIG. 9)

I 544 S-ZMPUT BUFFER me. a)

DATA

PATENTEU 3.728.575

SHEET 0U, 0F 23 Q; 92 03 @4 TI T2 3 4 T5 T6 T7 T8 CLOCK GENERATOR (SET) TQ| (cLRfiE I FF (SET) T02 L PATENTEU 3.728.575

Y sum 08 0F 23 INTENSITY A LEvEL SELECT Jw w d m TO FIGS. 28.830 Wm N 9.1 m f E? E m 0 50 d t 3 u D: O P o 5 DRAW FLAG E To FIGS I0,l8 a 36 v u N no P P P m m ,GATE sue. m H

AND COUNTER T0 FIGS. u 8 l2 v 2 NOT COMPARE DRAW PRESET m I Q 10 FIGS. :0 a as I g o 3 m 3' I II) 0) V cm. COUNTER 2% m g To FIG l3 Fl m m m 10 o m ENABLE sua.

AND COUNTER q T0 FIGS. I3 820 T m 9 t8 8 I v 03 STOP r m m COMPAREO TO FIG. l8 5 A a a STARTO (O rv N a, U) I? N o o 4 m m 40 up I m 0 0 I o 0' (D qm P m N m POSITION @l AWORD LOADED A To FIGS 11 8 12 z POSITION WORD N'- on i (\1 5% I m a 0 m qa: .vEcToR 'm WDRD LOADED m VECTOR WOR% To FIGS. |4,|8 cc ODR PATENTED W I 71375 saw 08 0F 23 PATENTED APR 1 7 [973 SHEET 12 [1F 23 w wmok BIT 3 BIT 3 PATENTEDAPR 1 71975 SHEET 13 OF 23 ihzo m 95 omm w o mnE o m mu OTM m PAIENTED APR 1 71975 COMPARE VECTOR DRAW I/ O CYCLE CYCLE STOP CYCLE CYCLE SHEET m 0F 23 Q GATE TO Xu ,Y AND OCTANT REGISTERS.

Q GATE TO T AND F-REGS. AND TO D/A CONVERTER FROM X AND Y.

D SET DRAW PRESET FLIP-FLOP.

Q CLEAR C-REG.,GATE X ANDY TO D/A CONVERTER, SET INTENSITY FLIP-FLOP l IF DRAW FLAG FLIP-FLOP SET.

@ SET DRAW FLAG FLIP-FLOP, ENABLE SUBTRACTOR AND COUNTER.

OPERATION TIMING CHART BEAM BLANKING CONTROL PATENTEDAPR 1 71975 SHEET 1a or 23 VECTOR WORD LOADED INTENSITY LEVEL (FIG .9)

m m F m m 

1. An electron beam speed control circuit for a cathode ray tube having a deflection system for moving the beam and wherein the smallest step the beam can be moved is a unit increment, said circuit comprising: a. first storage means for storing m bits representing present beam position, b. second storage means for storing m bits representing final beam position, c. a comparator coupled to said first and second storage means for comparing n of said m bits of said present beam position with n corresponding bits of said final beam position and producing an output signal when said bits compare, and d. control means coupled to said comparator and the deflection system for moving said beam in 2n 1 unit increments, said control means causing said beam to move in 2n unit increments when said output signal is produced by said comparing means.
 2. An electron beam speed control circuit for a cathode ray tube having a deflection system for moving the beam and wherein the smallest step the beam can be moved is a unit increment, said circuit comprising: a. first storage means for storing m bits representing present beam position, b. second storage means for storing m bits representing final beam position, c. a comparator coupled to both said storage means for comparing m- n bits of said present beam position with m- n corresponding bits of said final beam position and producing an output signal when said bits compare, and d. control means coupled to said comparator and the deflection system for causing said beam to move in 2n unit increments, said control means causing said beam to move in 2n 1 unit increments when said output signal is produced by said comparing means. 